I've used my Noctua NH-D14 as a passive cooler for a while with my 3570K at 4.1 GHz. It worked fine, temps got around 85-90C in prime. I would go with something like that instead if it will fit in your current rig. Also, if you can control your fans, it makes things very nice. i run my system entirely passive (except for my GPU's) until my MB temps reach certain thresholds.

Thanks for both reply's. I am aiming for completely silent as it sits next to the tv and the standard intel cooler drives me mad.Thought about things like closed loop water coolers but my brothers single rad cooler fan and pump are louder than the intel fan so that put me off. Will be building a complete new system soon so i guess it all comes down to what coolers fit on the new motherboards for Haswell. The Noctua NH-D14 coping at idle then spinning up a fan when needed might be the optimal answer. My system spends 95% of its life basically idle, I never turn it off as me and the gf are always just popping on and off it.

Thanks for both reply's. I am aiming for completely silent as it sits next to the tv and the standard intel cooler drives me mad.Thought about things like closed loop water coolers but my brothers single rad cooler fan and pump are louder than the intel fan so that put me off. Will be building a complete new system soon so i guess it all comes down to what coolers fit on the new motherboards for Haswell. The Noctua NH-D14 coping at idle then spinning up a fan when needed might be the optimal answer. My system spends 95% of its life basically idle, I never turn it off as me and the gf are always just popping on and off it.

You should be fine going with a Noctua NH-D14 or Dark Rock Pro 2. I can run them both passively WHILE gaming and be under the TJ Max for my 3570K, only by 10-15 degrees though. If it's a HTPC you'll be using it with, you'll be fine running passively or at very low RPM.